1997 Tour

Hasn't it been confirmed that Styx had Lou DePasqua, offstage, adding extra vocals, during the 1996 reunion tour? Is is safe to assume that he stuck with them for the 1997 tour.
I recently saw a video of them playing Queen Of Spades, in 1997. While I am certainly NOT suspecting any trickery, I noticed that the big, high note after the solo sounds like it might be another voice. Perhaps Lou handled it, off stage, to help Dennis?
https://youtu.be/3-jEeHcci0s?t=4m30s
I feel like the tone of that note seems a little to "shrill" to be Dennis's voice.
(Once again, I'm NOT suspecting lip syncing or anything.)
I recently saw a video of them playing Queen Of Spades, in 1997. While I am certainly NOT suspecting any trickery, I noticed that the big, high note after the solo sounds like it might be another voice. Perhaps Lou handled it, off stage, to help Dennis?
https://youtu.be/3-jEeHcci0s?t=4m30s
I feel like the tone of that note seems a little to "shrill" to be Dennis's voice.
(Once again, I'm NOT suspecting lip syncing or anything.)